Michelle Obama wears her favourite British label Preen at the Obama Foundation Summit

Michelle Obama is in Chicago this week for the inaugural Obama Foundation summit which gathers together the young leaders of the future.

The former First Lady wore a checked dress by Preen Line, the diffusion collection from Justin Thornton and Thea Bregazzi of London label Preen. While she was in the White House, Obama wore Preen's colourful, ladylike dresses numerous times, including for visits to Britain. She even invited the designers to a reception in Washington to celebrate their contribution.

However, today's choice shows the more experimental attitude she can adopt now that her husband is no longer President, with its relaxed, edgier look.

Whilst First Lady, Obama regularly promoted young American designers such as Thakoon, Jason Wu, Altuzarra and Proenza Schouler, as well as championing British brands from Christopher Kane to Roksanda.

Obama used her clothes and role as a style icon to communicate key messages, interweaving serious political messages and missions with a clear love of fashion.

Click through the gallery to see more Michelle Obama's style highlights...